During the period August 1977 to April 1978, 14 Black patients in Johannesburg area had systemic infections caused by Listeria monocytogenes. Nine of these patients were neonates who presented with septicaemia (5 cases) or septicaemia and meningitis (4 cases) and 5 were adults, all of whom had meningitis. The mortality rate was 43% (6/14), with 4 neonatal and 2 adult deaths. All isolates of L. monocytogenes were type 4b. Only sporadic cases of human listeriosis have previously been reported in South Africa, and the cases reported here constitute the first epidemic in this country.